Hawaii became the 50th and most recently admitted U.S. state in 1959.
President Dwight D. Eisenhower signed the Hawaii Admission Act on March 18, 1959. Hawaii voters approved statehood in a June 27 referendum, and Hawaii officially joined the Union on August 21, 1959. Its admission followed Alaska’s, which became the 49th state on January 3 of the same year.
Hawaii is an archipelago in the central Pacific Ocean. Its statehood history differs from that of most continental states because the islands were an independent kingdom, later a republic and U.S. territory, before admission. The Kingdom of Hawaii was overthrown in 1893, and the United States annexed the islands in 1898.
Hawaii’s admission completed the current fifty-state map. Alaska and Hawaii were the only states admitted during the twentieth century after the admission of Arizona in 1912, and their addition changed the national flag from 48 stars to 49 and then 50.